public/clock.html

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <title>Reloj</title>
  <!--
    CREDITS:
    http://codepen.io/dtinth/pen/tDihg
  -->
  <style>
  body {
      background: black;
  }

  .fill {
      position: absolute;
      top: 0;
      right: 0;
      bottom: 0;
      left: 0;
  }

  a {
      display: block;
      position: fixed;
      top: 0px; left: 0px;
      color: #fcc;
      text-decoration: none;
      padding: 4px;
      background: rgba(52,52,52,0.5);
      font: 12px Verdana, sans-serif;
      z-index: 1;
  }

  .clock {
      position: absolute;
      opacity: 1;
  }

  .fill .clock {
      left: 50%;
      top: 50%;
  }

  .centre {
      position: absolute;
      top: 50%;
      left: 50%;
      width: 0;
      height: 0;
  }

  .expand {
      position: absolute;
      top: 0;
      left: 0;
      transform: translate(-50%, -50%);
  }

  .anchor {
      position: absolute;
      top: 0;
      left: 0;
      width: 0;
      height: 0;
  }

  .element {
      position: absolute;
      top: 0;
      left: 0;
  }

  .round {
      border-radius: 296px;
  }

  .circle-1 {
      background: white;
      width: 12px;
      height: 12px;
  }

  .circle-2 {
      background: #FA9F22;
      width: 8px;
      height: 8px;
  }

  .circle-3 {
      background: black;
      width: 4px;
      height: 4px;
  }

  .second {
      transform: rotate(180deg);
  }

  .minute {
      transform: rotate(54deg);
  }

  .second-hand {
      width: 2px;
      height: 164px;
      background: #FA9F22;
      transform: translate(-50%,-100%) translateY(24px);
  }

  .hour {
      transform: rotate(304.5deg);
  }

  .thin-hand {
      width: 4px;
      height: 50px;
      background: white;
      transform: translate(-50%,-100%);
  }

  .fat-hand {
      width: 10px;
      height: 57px;
      border-radius: 10px;
      background: white;
      transform: translate(-50%,-100%) translateY(-18px);
  }

  .minute-hand {
      height: 112px;
  }

  .hour-text {
      position: absolute;
      font: 40px Hei, Helvetica, Arial, sans-serif;
      color: white;
      transform: translate(-50%,-50%);
  }

  .hour-10 {
      padding-left: 0.4ex;
  }
  .hour-11 {
      padding-left: 0.25ex;
  }

  .minute-text {
      position: absolute;
      font: 12px Avenir Next, Helvetica, Arial, sans-serif;
      color: white;
      transform: translate(-50%,-50%);
  }

  .minute-line {
      background: white;
      width: 1px;
      height: 9px;
      transform: translate(-50%,-100%) translateY(-131px);
      opacity: 0.34;
  }
  </style>
</head>
<body>
  <!--
Recreating Apple Watch's Utility face <http://www.apple.com/watch/design/> in HTML+CSS+JS
-->
<a href="http://codepen.io/dtinth/pen/cGxhl" target="_top">Check out the newer version!</a>

<div class="fill">
  <div class="reference"></div>
  <div class="clock" id="utility-clock">
    <div class="centre">
      <div class="dynamic"></div>
      <div class="expand round circle-1"></div>
      <div class="anchor hour">
        <div class="element thin-hand"></div>
        <div class="element fat-hand"></div>
      </div>
      <div class="anchor minute">
        <div class="element thin-hand"></div>
        <div class="element fat-hand minute-hand"></div>
      </div>
      <div class="anchor second">
        <div class="element second-hand"></div>
      </div>
      <div class="expand round circle-2"></div>
      <div class="expand round circle-3"></div>
    </div>
  </div>
</div>
<script>
var clock = document.querySelector('#utility-clock')
utilityClock(clock)

autoResize(clock, 295 + 32)

function utilityClock(container) {
    var dynamic = container.querySelector('.dynamic')
    var hourElement = container.querySelector('.hour')
    var minuteElement = container.querySelector('.minute')
    var secondElement = container.querySelector('.second')
    var minute = function(n) {
        return n % 5 == 0 ? minuteText(n) : minuteLine(n)
    }
    var minuteText = function(n) {
        var element = document.createElement('div')
        element.className = 'minute-text'
        element.innerHTML = (n < 10 ? '0' : '') + n
        position(element, n / 60, 135)
        dynamic.appendChild(element)
    }
    var minuteLine = function(n) {
        var anchor = document.createElement('div')
        anchor.className = 'anchor'
        var element = document.createElement('div')
        element.className = 'element minute-line'
        rotate(anchor, n)
        anchor.appendChild(element)
        dynamic.appendChild(anchor)
    }
    var hour = function(n) {
        var element = document.createElement('div')
        element.className = 'hour-text hour-' + n
        element.innerHTML = n
        position(element, n / 12, 105)
        dynamic.appendChild(element)
    }
    var position = function(element, phase, r) {
        var theta = phase * 2 * Math.PI
        element.style.top = (-r * Math.cos(theta)).toFixed(1) + 'px'
        element.style.left = (r * Math.sin(theta)).toFixed(1) + 'px'
    }
    var rotate = function(element, second) {
        element.style.transform = element.style.webkitTransform = 'rotate(' + (second * 6) + 'deg)'
    }
    var animate = function() {
        var now = new Date()
        var time = now.getHours() * 3600 +
                    now.getMinutes() * 60 +
                    now.getSeconds() * 1 +
                    now.getMilliseconds() / 1000
        rotate(secondElement, time)
        rotate(minuteElement, time / 60)
        rotate(hourElement, time / 60 / 12)
        requestAnimationFrame(animate)
    }
    for (var i = 1; i <= 60; i ++) minute(i)
    for (var i = 1; i <= 12; i ++) hour(i)
    animate()
}

function autoResize(element, nativeSize) {
  var update = function() {
    var parent = element.offsetParent
    var scale = Math.min(parent.offsetWidth, parent.offsetHeight) / nativeSize
    element.style.transform = element.style.webkitTransform = 'scale(' + scale.toFixed(3) + ')'
  }
  update()
  window.addEventListener('resize', update)
}
</script>
</body>
</html>